qswitch February 27, 2019 at 1:18 am
- This topic was modified 2 months, 4 weeks ago by qswitch.
I have the SA44B+TG44A Combo.
I am very satisfied with these devices,and the step from old software to the new Spike-software is a quantum leap, but i have a question.
Is it correct, that the amplitude of TG44A is -10dBm if “Sweep Type” is set to “Passive Device” and
is -30dBm if it is set to “Active Device” ?
And what are the settings (preamp/atten) of SA44B in this case?
I can’t find the information in spike and the manual of TG44A.
I do not want to kill my SA44B in a passive/active-device (filters+amplifiers) Scalar Network Analysis setup.
Is max. Input of SA44B with preamp off and atten set to 15dB: 20dBm? ,
and in case: atten set to 0dB: max-Input of SA44B is 5dBm or also 20dBm?
I suppose, there are also 2 small typing errors in TG44A-manual?
chapter 3.1, point 6. : “Set your reference level to +10 dBm.”
chapter 3.1, point 9. :”…select Active Device and change your reference level to +20 dBm. ”
It should be dB and not dBm,is it correct?
(or should i go back to sweep mode and set there the reference level in dBm?)
Regards and greetings from germany,
Justin CrooksModeratorJustin Crooks February 27, 2019 at 10:00 am
If you use “high dynamic range” scalar network analysis, the output power is both -10 dBm and -30 dBm in both cases. The damage level for the SA44B is +20 dBm regardless of attenuator setting (it could probably handle a bit more if the attenuator was set to 10-15 dB), but you can’t accurately measure signals above +10 dBm.
For passive high dynamic range, the pair of settings used is -30 dBm TG & -30 dBm SA (to 0 dB insertion loss), and -10 dBm TG & -50 dBm SA (for >40 dB insertion loss)
For “active” measurements, the SA reference level is moved up 20 dB I believe. The included 20 dB pad can be used to measure up to 40 dB of gain. To measure more gain than this, additional attenuation would be required.
If you are measuring an amplifier capable of more than +20 dBm output, I recommend using the 20 dB external attenuator. Or, more specifically, use enough attenuation so that if your amplifier saturates, it won’t blow the SA44B.
You are correct that scalar network analysis units should be dB, not dBm, but our software’s control panel (at least when the manual was written) required you to enter a dBm reference level, and used this as dB. This may have been fixed since then.
qswitchParticipantqswitch February 27, 2019 at 10:47 pm
thank you for the information and the quick response.
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